The present disclosure generally relates to seismic data acquisition, and more specifically to ocean bottom seismic data acquisition systems.
Petrochemical products such as oil and gas are ubiquitous in society and can be found in everything from gasoline to children's toys. Because of this, the demand for oil and gas remains high. In order to meet this high demand, it is important to locate oil and gas reserves in the Earth. Scientists and engineers conduct “surveys” utilizing, among other things, seismic and other wave exploration techniques to find oil and gas reservoirs within the Earth. These seismic exploration techniques often include emitting seismic energy into the Earth with a seismic energy source (e.g., air guns, vibrators, dynamite, etc.), and monitoring the Earth's response to the seismic source with one or more receivers in order to create an image of the subsurface of the Earth.
The response of the Earth to the seismic energy is typically recorded at a plurality of receivers that may be, for example, towed behind an acquisition vessel in a marine survey, or deposited on a seafloor. In the situation wherein the plurality of receivers are deposited on a seafloor, an acoustical source, for example, towed by a source vessel on a surface of the sea, may be used to direct acoustical waves towards the seafloor. The acoustical waves may penetrate the seafloor and continue to travel through the seabed. Boundaries within the seabed, however, may result in acoustical reflections. Thus, the plurality of receivers on the seafloor may receive the acoustical waveforms in the form of seismic wavefields as the waves are reflected back towards the seafloor from the boundaries in the seabed. The plurality of receivers on the seafloor may include one or more sensors, including a particle motion sensor, a pressure sensor, or both a particle motion sensor and a pressure sensor in proximity to one another. The particle motion sensor may be, for example, a three-component geophone or accelerometer that records vectorial velocity measurements of a reflected seismic wavefield. The pressure sensor may be, for example, a hydrophone that records scalar pressure measurements of the reflected seismic wavefield. By observing the reflected seismic wavefield detected by the receivers during the survey, geophysical data pertaining to the reflected signals may be acquired and this data may be used to form an image indicative of the subsurface near the survey location.
The resolution of the seismic survey is related to the resolution of the collected data, which is itself related to the density of source acoustical waveforms projected from the surface of the sea. A high resolution may require a corresponding high number of source waveforms, which may require a significant amount of time or resources. Efforts to reduce the time or resources, while balancing the time during which resources are used, may be desired.